Telecommunications regulatory bodies commonly allocate different portions of the radio spectrum for disparate uses, and may license rights to use various channels (e.g., frequency bands) within given portions of the radio spectrum. For instance, a portion of the radio spectrum can be allocated by a telecommunications regulatory body for broadcast service; such portion of the radio spectrum can be referred to as a broadcast spectrum. The telecommunications regulatory body may assign licenses to various licensees to use channels in the broadcast spectrum. Thus, a licensee may be allotted rights to use a particular channel from the broadcast spectrum in a geographic region. Further, the licensee may be assigned rights to use the particular channel from the broadcast spectrum during a given period of time.
However, some channels within the broadcast spectrum may be unused at a particular location during a given time period. These channels can be referred to as whitespaces. For example, the telecommunications regulatory body can assign whitespaces (e.g., as guard bands) between channels to mitigate interference. Moreover, whitespaces can naturally exist between used channels, since assigning nearby transmissions to immediately adjacent channels can cause destructive interference to both channels. Further, there may be unused channels within the broadcast spectrum; for instance, an unused channel may have been previously unassigned by the telecommunications regulatory body or such channel may have become unassigned due to technology changes (e.g., previously assigned but presently unassigned). According to an example, the switchover from analog television to digital television freed various channels in the broadcast spectrum. In the United States, analog television broadcasts typically occurred between 54 MHz and 806 MHz prior to the transition to digital television, while the frequency band from 698 MHz to 806 MHz is generally unused for digital television broadcasts subsequent to the transition to digital television.
Various proposals have advocated using whitespaces in the broadcast spectrum to provide wireless broadband Internet access or for unlicensed use in general. A device configured to use these available channels can be referred to as a whitespace device. In some conventional approaches, the whitespace device can be designed to detect available channels in the broadcast spectrum and utilize at least a subset of the channels detected as being available for communications (e.g., transmit signals from the whitespace device over such channel(s), receive signals at the whitespace device over such channel(s), etc.). Thus, in such conventional approaches, the whitespace device commonly searches for channels which lack transmissions from assigned licensees (e.g., television broadcasters, wireless microphones, etc.); yet, such an approach can be costly, inefficient, and difficult to implement.
More recently, a database approach for detecting whitespaces has been proposed. For instance, a regulatory authorized database can be populated with information pertaining to assigned licensees within the broadcast spectrum (e.g., television broadcasters, wireless microphones, etc.). A whitespace device can query the regulatory authorized database for available channels at a location of the whitespace device during a time period. In response, the whitespace device can receive a list of the available channels at the location for the time period, where the time period can depend upon jurisdiction (e.g., two hours, twenty four hours, etc.).